CVE search · CVE-2026-52845
CVE-2026-52845
high 8.1
Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, forward_auth copy_headers deletes the exact client-supplied identity header before copying the trusted value from the auth gateway. But when the request later goes through php_fastcgi, Caddy normalizes HTTP headers into CGI variables by replacing - with _. This lets a client send an underscore alias that survives the forward_auth delete step but becomes the same PHP/FastCGI variable. Result: a remote client can inject or sometimes override identity/group headers trusted by PHP/FastCGI applications behind Caddy. This vulnerability is fixed in 2.11.4.
Details
- Status
- Modified
- Published
- Last changed
- Source
- security-advisories@github.com
Severity
| Version | Score | Vector | Source |
|---|---|---|---|
| CVSS 3.1 | high 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N |
security-advisories@github.comSecondary |
| CVSS 3.1 | high 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N |
0b0ca135-0b70-47e7-9f44-1890c2a1c46cSecondary |
Affected products
Vendor and product from the NVD’s CPE applicability statements. Versions and conditions are on the NVD’s page.
- caddyserver · caddy
References
- https://github.com/caddyserver/caddy/security/advisories/GHSA-f59h-q822-g45gExploitThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2026-52845
- https://bugzilla.redhat.com/show_bug.cgi?id=2491907
- https://github.com/caddyserver/caddy/security/advisories/GHSA-f59h-q822-g45gExploitThird Party Advisory
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52845.json